JPH0852506A - Method for controlling tension of skin pass mill and device therefor - Google Patents

Abstract

PURPOSE:To improve the deviation accuracy of elongation percentage without necessitating the fixazation of the optimum value of gain or the accumlation of data for setting. CONSTITUTION:The elongation percentage of metal plate is calculated by the difference of the number of revolution within the same time of right and left deflector rolls 4, 5 which are respectively provided between main rolls 1 and right and left reels 2, 3, travel length per unit time of the metal plate on the inlet side is calculated from the rotational amounts of the right and left deflector rolls 4, 5 and the deviation DELTAepsilon of elongation percentage is determined from a preset set value epsilon SET of elongation percentage and calculated value of elongation percentage. The frequency of the deviation of elonation percentage over the deviation reference for switching gain is counted for every travel length per unit time, control gain is decreased when the count value exceeds a preset value, and the control gain is increased when the frequency of inversion of positive and negative signs of the deviation of elongation percentage in the midway of the travel length per unit time is not more than the preset value. The compensation amount of elongation percentage of tension determined from the deviation DELTAepsilon and a gain determined with a gain switching part 13 is outputted to the control part 14 and the tension control of the reels 2, 3 is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a pair of main rolls and a pair of left and right reels, and a method and apparatus for controlling the tension of a skin pass mill in which the elongation control is performed by controlling the tension of the rear reel (the reel on the unwinding side). Regarding

[0002]

2. Description of the Related Art A skin pass mill is one of the hot rolling and refining equipment for steel sheets. This is a facility for cooling the hot coil to room temperature and performing a light reduction with a reduction rate of 0.1 to 3% to evenly extend the sheet material because the steel sheet as rolled by the hot strip mill has poor flatness. . The skin pass mill is composed of a pair of main rolls that roll down the plate material and left and right reels that wind the plate material, and flatten the plate material while controlling the tension of the rear reel. Conventionally, when the elongation rate is controlled by controlling the tension of the rear reel, the gain for calculating the elongation rate compensation amount output of the tension includes a partial differential element in the calculation. Therefore, the elongation rate control is PI control in the control device, and the gain The control parameters such as the integration time and the integration time are fixed values or set values in the control device.

[0003]

However, since the optimum value of the gain differs depending on the steel type and the plate thickness of the steel sheet, in the prior art, in order to set the optimum value of the gain, the type of the steel type and the plate thickness. It is necessary to collect a large amount of data for each time, and if the data is not accurate, it will cause an error. Further, if different steel grades and thickness parameters are set for the steel sheet to be processed, there is a problem in that there is an error in the thickness of the product as well. Therefore, the problem to be solved by the present invention is that it does not require a large amount of data for setting the optimum gain value, and even if the gain is roughly set, the accuracy of elongation deviation is increased to improve the product plate thickness. It is to improve accuracy.

[0004]

In order to solve the above problems, a tension control method for a skin pass mill according to the present invention comprises a pair of upper and lower main rolls through which a plate material is passed and left and right reels for winding the plate material, In the tension control method of the skin path mill, which controls the tension of one of the left and right reels to be unwound, and performs the backup control by the pressure system, the left and right deflector rolls installed between the main roll and the left and right reels, respectively. The elongation rate ε of the plate material is calculated based on the difference in the number of revolutions within the same time, and the traveling time per unit time of the plate material is calculated based on the rotation amount of the left and right deflector rolls per unit time. set value epsilon _sET and obtains a growth rate deviation Δε by the elongation calculation value epsilon mentioned above calculation, for each of the unit time running length, preset the elongation difference Δε gain Comparing the deviation reference for Toggles, elongation rate deviation Δ in the unit time running length in
OVCNT is counted the number of times ε exceeds the deviation reference, and when the count value exceeds a preset count value OVSET, the control gain is decreased, and the elongation rate deviation Δε passes 0 for each unit time running. Then, CHCNT is counted the number of times the sign has changed, and when the count value becomes equal to or less than the preset count value CHSET, the control gain is increased and the tension obtained by the elongation rate deviation Δε and the value of the control gain. The tension control of the reel is performed so as to compensate the elongation compensation amount ΔT.

[0005]

With the above-mentioned means, the variation of the elongation percentage deviation per unit time running length is monitored, and when the number of variations is large, the gain is decreased because it means that the gain is high and hunting is likely. , Growth rate deviation is quite 0
If it is not settled to, it means that the gain is too low and the response is slow.By increasing the gain, the target coils are automatically adjusted to have the appropriate expansion rate control gain. Achieve precision improvement of product thickness.

[0006]

EXAMPLES The present invention will be specifically described below with reference to examples. FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a flow chart. 1 is a main roll, 2 is a left reel, 3 is a right reel, 4 is a left deflector roll, 5
Is a right deflector roll, 6 is a pulse generator that detects the rotation amount of the left deflector roll 4, that is, the plate traveling amount, 7 is a rotation amount of the right deflector roll 5, that is, a pulse generator that detects the plate traveling amount, and 8 is the left A first calculation unit that outputs a calculated elongation rate from the outputs of the pulse generator 6 of the deflector roll and the pulse generator 7 of the right deflector roll. Similarly, 9 is the output of the pulse generators 6 and 7 of the left and right deflector rolls. The second calculation unit that outputs the plate running length on the entry side based on the amount, 10 is a setting unit that sets the elongation rate setting value ε _SET , and 11 is the elongation rate deviation Δε from the elongation rate calculation value ε and the elongation rate setting value ε _SET. The third arithmetic unit 12 outputs the deviation reference for gain switching, which has a preset elongation deviation Δε for each unit running length on the ingress side, during which the positive and negative are alternately exceeded. A comparison unit that counts the number of times of passing and the number of times the sign of change in elongation percentage deviation Δε has passed 0, 13 determines gain switching based on the count value from the comparison unit 12, and outputs a gain setting value. The gain switching unit 14 is a control unit that outputs a tension compensation amount by PI elongation rate control based on the elongation rate deviation output and the gain setting value output. In the figure, 15 and 16 are left and right reels 2, respectively.
3 drive motor.

Next, the operation will be described with reference to rightward rolling. At this time, the left side is the entrance side and the right side is the exit side.
The number of pulses generated by the pulse generator per revolution of the left and right deflector rolls 4 and 5 is P ₁ , P ₂ [pulses / revolution], the number of pulses generated by the pulse generator of the left and right deflector rolls 4 and 5 per unit time is C ₁ , C ₂ [pulse], roll diameters of the left and right deflector rolls 4, 5 are D ₁ ,
Assuming D ₂ [m], the elongation rate calculated value ε is

[Equation 1] Then, this value is obtained by the first calculation unit 8.

The elongation set value by the elongation setting unit 10 is set to ε
_{If SET} (step 100 in FIG. 2), the third operation unit 1
Elongation ratio at 1 deviation [Delta] [epsilon] [%] is, Δε = ε _SET -ε next, and outputs this value to the control unit 14 (Step 11
0,120). Further, the second operation unit 9 obtains the entry side plate running length, and based on this length, the timing of the unit time running length is created. Next, the control counter is created in the comparison unit 12 at a time between each unit time traveling length. Set the counter for detecting the elongation deviation that is caused by the large control gain to 0.
VCNT, and counts up when it exceeds the elongation percentage deviation standard for the first time after exceeding 0 from the positive and negative sides (Fig. 3,
Step 130). In addition, the counter for detecting the elongation deviation due to the small control gain is CHCNT,
When the growth rate deviation Δε exceeds 0 from the positive / negative opposite side, it is counted up (FIG. 4, step 140).

Next, the counter value for reducing the gain is set to OV.
SET is set, and OVCNT and OVSET are compared for each unit traveling length (step 150). If OVCNT ≧ OVSET, a gain decrease signal is output to the gain switching unit 13 (steps 160 and 170). Similarly, the counter value for increasing the gain is set to CHSET, and CHCNT and CHSET are compared for each unit traveling length. If CHCNT ≦ CHSET, a gain increase signal is output to the gain switching unit 13 (steps 180 and 190). OVCNT, CH
Both CNTs are cleared for each unit running length (step 200). Next, the gain switching unit 13 inputs a gain increase / decrease signal to increase / decrease the gain. If the previous gain is G _N-1 , the current gain is G _N , and the increase / decrease amount is ΔG, then G _N = G _N-1 ± ΔG. This value is output to the control unit 14.

Next, in the control unit 14, when the outgoing side plate thickness is h ₂ , the rolling force is P, the incoming side tension is T, the mill constant is M, the plate cross-sectional area is S, and the tension elongation compensation amount is ΔT, ΔT is

[Equation 2] Becomes By applying the gain output G _N of the gain switching unit 13 to A in the above equation, the operation proceeds in the direction of converging the elongation percentage deviation Δε. The elongation rate compensation amount ΔT of the tension is applied to the drive motor 15 of the left reel 2 to control the tension.

[0011]

As described above, according to the present invention, the elongation percentage deviation is always evaluated and automatically adjusted to obtain the optimum gain. Therefore, even if the initial gain setting is rough,
The optimum gain for the steel type and the plate thickness can be obtained, whereby the accuracy of the elongation percentage deviation can be increased and the accuracy of the product plate thickness can be improved. Further, unlike the conventional case, it is possible to prevent a decrease in accuracy due to an erroneous setting without requiring a work of collecting a large amount of data for obtaining the optimum gain value for each steel type and plate thickness.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart of an embodiment of the present invention.

FIG. 3 is a time chart showing changes in the elongation rate calculation value when the control gain is large.

FIG. 4 is a time chart showing changes in the elongation rate calculation value when the control gain is small.

[Explanation of symbols]

1 main roll, 2 left reel, 3 right reel, 4 left deflector roll, 5 right deflector roll, 6 left deflector roll plate travel amount detection pulse generator, 7
Right deflector roll plate travel amount detection pulse generator, 8 first calculation section, 9 second calculation section, 10 target elongation setting section, 11 third calculation section, 12 comparison section, 13 gain switching section, 14 control section, 15 , 16 Drive motor

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B21C 47/00 F B65H 23/192 Z 77/00

Claims (2)

[Claims] 1. A pair of upper and lower main rolls through which a plate material is threaded and left and right reels for winding the plate material are provided, the tension of one of the left and right reels to be unwound is controlled, and backup control by a pressure system is performed. In the tension control method of the skin pass mill, the elongation rate ε of the plate material is calculated by the difference in the number of rotations of the left and right deflector rolls respectively installed between the main roll and the left and right reels within the same time, and the left and right rolls are similarly processed. A unit time running length on the entrance side of the plate material is calculated by the rotation amount of the deflector roll per unit time, and an elongation percentage deviation Δε is obtained by a preset elongation percentage set value ε _SET and the calculated elongation percentage calculated value ε. For each unit time traveling length, the elongation percentage deviation Δε is compared with a preset deviation standard for gain switching, and the elongation percentage deviation Δε within the unit time traveling length is The number of times OVCNT that exceeds the deviation standard is counted, and when the count value exceeds the preset count value OVSET, the control gain is decreased, and the elongation rate deviation Δε passes 0 every time the unit time travels. Count CHCNT the number of times the code changes,
When the count value becomes equal to or less than the preset count value CHSET, the control gain is increased so as to compensate the elongation rate compensating amount ΔT of the tension obtained by the elongation rate deviation Δε and the value of the control gain. A tension control method for a skin pass mill, comprising controlling the tension of the reel. 2. A pair of upper and lower main rolls through which a plate material is passed and left and right reels for winding the plate material are provided, the tension of the reel to be unwound among the left and right reels is controlled, and backup control by a pressure system is performed. In a tension control device for a skin pass mill that performs the above, first, the elongation rate of the plate material is calculated by the difference in the rotational speeds of the left and right deflector rolls installed between the main roll and the left and right reels within the same time.
A calculation unit, a second calculation unit that similarly calculates a unit time running length on the entrance side of the plate material based on the rotation amount of the left and right deflector rolls in a unit time, a setting unit that sets an elongation rate set value ε _SET in advance, A third arithmetic unit that outputs an elongation rate deviation Δε from the calculated elongation rate calculation value ε and the elongation rate setting value ε _SET; and an elongation rate deviation Δε and preset gain switching for each unit time running length. Compare with deviation criteria,
The number of times OVCNT in which the elongation percentage deviation Δε within the unit time running length exceeds the deviation reference is counted, and the number of times CHCNT in which the elongation percentage deviation Δε passes through 0 and the sign changes for each unit time running is calculated. A comparing unit that counts, and decreases the control gain when the count value OVCNT exceeds a preset count value OVSET, and increases the control gain when the count value CHCNT becomes equal to or less than the preset count value CHSET. A tension switching rate compensation amount Δ based on the gain switching section and the elongation rate deviation Δε and the gain obtained by the gain switching section.
A tension control device for a skin pass mill, comprising: a control unit that outputs T.